There is a recognized need for holsters that have a device which prevents the unauthorized removal of an automatic pistol or a revolver by someone other than the wearer. This need has inspired a variety of different inventions that provide for restraint of revolvers or automatic pistols within a holster. The present invention is designed to better restrain automatic or semiautomatic pistols against removal by others, within a holster that has flexible side walls; while permitting a natural draw. The device of the invention restrains the pistol within the holster from the inside of the trigger guard and allows removal of the pistol from the holster only by the wearer through the top opening of the holster. A number of holsters are known, many of which include restraining devices of other kinds which prevent the removal of the pistol from the holster but do not engage inside the trigger guard. See, for example, U.S. Pat. No. 3,420,420 (E. J. Clark), U.S. Pat. No. 1,113,530 (F. H. Audley), U.S. Pat. No. 4,256,243 (Bianchi et al), U.S. Pat. No. 4,277,007 (Bianchi et al), U.S. Pat. No. 1,320,751 (Freyer), U.S. Pat. No. 1,844,603 (Sarson), U.S. Pat. No. 2,001,321 (Berns), U.S. Pat. No. 2,577,869 (Adams) and U.S. Pat. No. 3,942,692 (Chica). Many of these prior art holsters use restraints which engage either the outside of the trigger guard or the butt of the pistol to prevent removal through the top opening of the holster. Some of these prior art holsters use springs to either maintain the pistol in position within the holster or to keep the pistol engaged with the restraining device. Only two of these prior art holsters are known to have a restraining device which engages the inside of the trigger guard. U.S. Pat. No. 1,113,530 (F. H. Audley), uses a restraining device, called H3, that enters the trigger guard to hold the pistol within the holster, but requires that the restraining device be released by first physically pulling the restraint out of the trigger guard and then drawing the pistol. U.S. Pat. No. 4,277,007 (Bianchi et al), has a device which enters the trigger guard to prevent the pistol from being drawn out through the top opening of the holster but in order for the invention to work the pistol must be drawn forward through an opening in the front wall of the holster, U.S. Pat. No. 3,942,692 (Chica), uses a holster which restrains the gun by means of a nylon welt which engages the back of the trigger guard, between the gun handle and the trigger, and is maintained in that position by means of a spring in the front wall of the holster. This holster requires that the pistol used have a trigger guard which can engage the nylon welt in the above described manner while the present invention merely requires that the inside of the trigger be engaged and therefore an automatic pistol having the rear portion of its trigger guard as an integral part of the handle of the gun can be used with the present invention whereas the prior art device could not be used. In addition the present restraint is more secure. Finally, all prior art devices known to the inventor make modifications to the outside as well as the inside of the holster, while the modifications we make to the holster are all contained inside of the holster. Therefore, there is nothing about the outward appearance of the holster which would indicate its true nature and function to a potential adversary.